1. Field of the Invention
The present invention relates to a photo film winding method and a winder apparatus for a photo film cassette. More particularly, the present invention relates to a photo film winding method and a winder apparatus for winding photo film about a spool of a cassette being produced by rotating the spool.
2. Description Related to the Prior Art
U.S. Ser. No. 787,802 (corresponding to JP-A 5-224351) suggests a photo film cassette of the IX240 type, which is constructed so that, when the spool is rotated in a direction to unwind the photo film, a leader of the photo film is advanced through the photo film passage port to the outside of the cassette shell.
U.S. Pat. No. 5,462,240 (corresponding to JP-A 6-35128) discloses a method of producing the photo film cassette of the IX240 type. With reference to FIG. 1, flange disks 4a and 4b are mounted on axial ends of a spool core 4c, to obtain a spool 4. Respective shell halves 3a and 3b are molded by injection molding. A cassette shutter 5 is placed on the shell half 3b, on which the shell half 3a is fitted. Junctures between the shell halves 3a and 3b are welded by ultrasonic welding to attach the shell halves 3a and 3b, at the cassette shell 3 so that a photo film cassette 6 is obtained.
Then a trailer of a strip of photo film 7 is passed through a photo film passage port 3c, and secured to a trailer retainer 4g of the spool core 4c. The spool 4 is rotated to draw and wind the photo film 7 into it.
In FIG. 8, a conventional photo film winder apparatus is illustrated. The photo film cassette 6 after assembly is set in a cassette holder 90. The photo film 7 is passed between two tension rollers 93 and 94. The trailer of the photo film 7 is inserted in the photo film cassette 6. After the trailer is secured to the spool 4, (see FIG. 1) a drive shaft 95a is connected to a key-receiving first end 4i of the spool 4 with a key way. The drive shaft 95a is rotated by a motor 95 to draw and wind the photo film 7 into the photo film cassette 6. While the photo film 7 is wound, a brake mechanism 96 brakes the tension roller 94 so that the tension rollers 93 and 94 apply tension to the photo film 7 being wound. One of the two axial ends of the spool 4 opposite to the drive shaft 95a is pressed against a portion about a bearing hole 3g, because the one axial end is pulled in a direction from the spool 4 toward the tension rollers 93 and 94. The axial end is likely to push its bearing hole so forcibly that plastic dust or powder is created by scratches formed between them.